Imports System.IO 

Module Module1 

   Sub Main() 

     'purpose: open a file and append infromation to its end 

     'local scope 
     Dim fileStream As FileStream 
     Dim streamWriter As StreamWriter 
     Dim streamReader As StreamReader 

     'create a new instance of the file stream object 
     'note:  if the file does not exist, the constructor create it 
     fileStream = New     fileStream(path:="c:\test.txt", _ 
        mode:=FileMode.OpenOrCreate, access:=FileAccess.Write) 

     'create an instance of a character writer 
     streamWriter = New StreamWriter(stream:=fileStream) 

     'set the file pointer to the end of the file 
     streamWriter.BaseStream.Seek(offset:=0, origin:=SeekOrigin.End) 

     'write a line of text to the end of the file 
     streamWriter.WriteLine(value:="This is a test") 
 
     'apply the update to the file 
     streamWriter.Flush() 

     'close the stream writer 
     streamWriter.Close() 

     'close the file stream object 
     fileStream.Close() 

     'create a new instance of file stream to read the file back 
     fileStream = New fileStream(path:="c:\test.txt", _ 
        mode:=FileMode.OpenOrCreate, access:=FileAccess.Read) 

     'create a stream reader instance 
     streamReader = New StreamReader(stream:=fileStream) 

     'set the file pointer to the start of the file
     streamReader.BaseStream.Seek(offset:=0, _ 
        origin:=SeekOrigin.Begin) 

     'loop through the file and write to console until the 
     ' end of file reached 
     Do While streamReader.Peek > -1 
          Console.WriteLine(value:=streamReader.ReadLine()) 
      Loop 

      'close the stream reader 
      streamReader.Close() 

      'wait for the user to stop the console application 
      Console.WriteLine("Press 's' to stop the application.") 

      'loop until users presses s key 
      Do While Console.ReadLine <> "s" : Loop 
   End Sub 
End Module

Visual basic (VB.net) Online Compiler

Write, Run & Share VB.net code online using OneCompiler's VB.net online compiler for free. It's one of the robust, feature-rich online compilers for VB.net language, running on the latest version 16. Getting started with the OneCompiler's VB.net compiler is simple and pretty fast. The editor shows sample boilerplate code when you choose language as VB.net. OneCompiler also has reference programs, where you can look for the sample code to get started with.

Read input from STDIN in VB.net

OneCompiler's VB.net online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample VB.net program which takes name as input and prints hello message with your name.

Public Module Program
	Public Sub Main(args() As string)
	 Dim name as String = Console.ReadLine()    ' Reading input from STDIN
   Console.WriteLine("Hello " & name)           ' Writing output to STDOUT
	End Sub
End Module

About VB.net

Visual Basic is a event driven programming language by Microsoft, first released in the year 1991.

Key Features

  • Beginner's friendly language.
  • Simple and object oriented programming language.
  • User friendly language and easy to develop GUI based applications.

Syntax help

Variables

Variable is a name given to the storage area in order to identify them in our programs.

Simple syntax of Variable declaration is as follows

Dim variableName [ As [ New ] dataType ] [ = initializer ]

Variable initialization

variableName = value

Conditional Statements

1. If

If condition-expression Then 
    'code
End If

2. If-else

If(conditional-expression)Then
   'code if the conditional-expression is true 
Else
  'code if the conditional-expression is false 
End If

3. If-else-if ladder

If(conditional-expression)Then
   'code if the above conditional-expression is true 
Else If(conditional-expression) Then
        'code if the above conditional-expression is true 
    Else
        'code if the above conditional-expression is false 
End If

4. Nested-If

If(conditional-expression)Then
   'code if the above conditional-expression is true
   If(conditional-expression)Then
         'code if the above conditional-expression is true 
   End If
End If

5. Select Case

Select [ Case ] expression
   [ Case expressionlist
      'code ]
   [ Case Else
      'code ]
End Select

Loops

1. For..Next

For counter [ As datatype ] = begin To end [ Step step ]
   'code
   [ Continue For ]
   'code
   [ Exit For ]
   'code
Next [ counter ]

2. For..Each

For Each element [ As datatype ] In group
   'code
   [ Continue For ]
   'code
   [ Exit For ]
   'code
Next [ element ]

3. While

While conditional-expression
   'Code 
   [ Continue While ]
   'Code
   [ Exit While ]
   'Code
End While

4. Do-while

Do { While | Until } conditional-expression
   'Code
   [ Continue Do ]
   'Code
   [ Exit Do ]
   'Code
Loop

Do
   'Code
   [ Continue Do ]
   'Code
   [ Exit Do ]
   'Code
Loop { While | Until } conditional-expression

Procedures

Procedure is a sub-routine which contains set of statements. Usually Procedures are written when multiple calls are required to same set of statements which increases re-usuability and modularity.

Procedures are of two types.

1. Functions

Functions return a value when they are called.

[accessModifiers] Function functionName [(parameterList)] As returnType
   'code
End Function

2. Sub-Procedures

Sub-procedures are similar to functions but they don't return any value.

Sub ProcedureName (parameterList)
'Code
End Sub